The fall season in gender-gap news has started early and with a bang. A study released yesterday in the Journal of the American Medical Association shows that male doctors earn over 25% more than female doctors. Why am I not surprised? There is a constant stream of stories showing gender disparities like this: that Obama gave only 35% of Cabinet-level posts to women, that men still write 87% of Wikipedia entries, that they are approximately 80% of local news-television and radio managers, and over 75% of philosophers.

After decades of antidiscrimination laws, diversity initiatives and feminist advocacy, such data leads to an uncomfortable question: Do women actually want equality? The answer seems transparently, blindingly, obvious. Do women want to breathe fresh air? Do they want to avoid rattlesnakes and fatal heart attacks?

But from another perspective, the answer is anything but clear. In fact, there’s good reason to think that women don’t want the sort of equality envisioned by government bureaucrats, academics and many feminist advocates, one imagined strictly by the numbers with the goal of a 50-50 breakdown of men and women in C-suites, law-school dean offices, editorial boards and computer-science departments; equal earnings, equal work hours, equal assets, equal time changing diapers and doing the laundry. “A truly equal world,” Sheryl Sandberg wrote in Lean In, which is still on the best-seller lists months after its spring publication, “would be one where women ran half our countries and companies and men ran half our homes.” It’s a vision of progress that can only be calculated through the spreadsheets of labor economists, demographers and activist groups.

It would be silly to deny that equality-by-the-numbers researchers can deliver figures that could alarm even an Ann Romney. There’s the puny 4.2% of female Fortune 500 CEOs, the mere 23.7% of female state legislators, the paltry 19% of women in Congress. But while “numbers don’t lie,” they can create mirages that convince us we see something we don’t. Take, for example, the JAMA study about the pay gap between male and female doctors. The study seems to capture yet another example of discrimination against women. But because it fails to consider differences in medical specialty or type of workplace, that appearance may well be an illusion. Surgeons and cardiologists, who have long been in the ranks of the top-earning specialties, remain predominantly male. Meanwhile, as women flooded the profession, they disproportionately chose to become psychiatrists and pediatricians, specialties that have always been among the least lucrative.

There are reasons for this particular wage gap that are gender-blind. Surgeons need more years of training, perform riskier work (at least that’s how malpractice insurers see it) and put in more unpredictable hours. Unsurprisingly, according to surveys, women who become doctors approach their work differently than men. They spend more time with each patient; when choosing jobs, they are far more likely to cite time for family and flexible hours as “very important” and to prefer limited management responsibilities. Male doctors, on the other hand, are more likely to think about career advancement and income potential.

This hints at the problem with the equality-by-the-numbers approach: it presumes women want absolute parity in all things measurable, and that the average woman wants to work as many hours as the average man, that they want to be CEOs, heads of state, surgeons and Cabinet heads just as much as men do. But a consistent majority of women, including those working full time, say they would prefer to work part time or not at all; among men, the number is 19%. And they’re not just talking; in actual practice, 27% of working women are on the job only part time, compared with 11% of men.

Now, a lot of people might say that American women are stymied from pursuing their ambitions because of our miserly maternity leave, day care and workplace-flexibility policies. But even women in the world’s most family-friendly countries show little interest in the equality-by-the-numbers ideal. In Iceland, Norway, Sweden and Finland, according to the OECD, women still work fewer hours and earn less money than men; they also remain a rare sight in executive offices, computer-science classrooms and, though the OECD doesn’t say it I’m willing to bet, philosophy conferences. Sweden, the gold standard of gender equality in many minds, has one of the highest percentages of women working part time anywhere in the world. Equality-by-numbers advocates should be thinking about women’s progress in terms of what women show that they want, not what the spreadsheets say they should want.